Integrated circuits (IC's) are designed to operate at a certain speed at a given nominal voltage. Due to variations in the materials used and/or in a fabrication process by which they are formed, IC's that are intended to be identical may operate at different speeds when supplied with the nominal voltage. The speeds of individual devices may be determined during production testing, and an indication related to the speed of a particular device may be stored on the IC in a non-volatile manner. For example, it is known to store information related to the speed of an IC in one-time programmable registers such as fuse bits. The stored information may identify the actual voltage that is required for the particular IC to perform at its rated operating speed or it may identify an offset or delta from the nominal operating voltage.
A given IC may include an adaptive voltage scaling (AVS) controller that controls the voltage at which a portion of the IC operates. The AVS controller may, for example, read information about an operating voltage that was stored in the IC during production testing and control the operating voltage of the IC accordingly. AVS controllers may also use information about the state of the IC and/or its environment to control a voltage. For example, certain IC's may operate faster as the temperature of the IC increases. An AVS controller will thus reduce the voltage supplied to that IC when a temperature increase is detected and increase the voltage when a temperature decease is detected. Other operating states, such as the frequency at which a portion of the IC is operating, may also affect power consumption, and the AVS controller may monitor these states and control a voltage provided to the IC as the various monitored states change.
While conventional AVS controllers can provide power savings by reducing a voltage supplied to a portion of an IC, such savings require processing power to achieve. That is, a processor on the IC must analyze sensor signals and make the desired voltage adjustments. Thus reducing power consumption can also reduce the performance of the IC or a device controlled by the IC. It would therefore be desirable to provide a method and system of AVS that has a reduced impact on system performance.